<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    p {
      color: blue;
    }

    a {
      text-decoration: none;
    }

    .success {
      border: solid 5px green;
    }

    .fail {
      border: solid 5px red;
    }
  </style>
</head>

<body>
  <p>hello,world </p>
  <a href="#">go</a>

  <div class="success">okokok</div>

  <div class="fail">error</div>
</body>

</html>